Double-hung balanced take-out window



4 Sheets-Sheet 1 F. E. ADAMS I DOUBLE-HUNG BALANCED TAKE-OUT WINDOW INVENTOR. W3 E Wm Dec. 13, 1966 Filed Jun 4, 1964 F. E- ADAMS DdUBLE-HUNG BALANCED TAKE-OUT WINDOW Dec. 13, 1966 4 Sheets-Sheet 2 Filed June 4, 1964 Dec. 13, 1966 E, ADAMS 1 3,290,825

DOUBLE-HUNG BALANCED TAKE-OUT WINDOW Filed June 4, 1964 4 Sheets-Sheet 3 Fig.1 3

IN VEN TOR. BY M E. wow/J W N minnow Dec. 13, 1966 F. E. ADAMS 3,290,325

DOUBLE-HUNG BALANCED TAKE-OUT wmnow 4 Sheets-Sheet 4 Filed June 4, 1964 3 I W F1916 19 20:59-

INVENTOR. M i. prdcww BY WL-VWJ United States Patent 3,290,825 DOUBLE-HUNG BALANCED TAKE-OUT WINDOW Frank E. Adams, Walton Road, Seahrook, N.H. Filed June 4, 1964, Ser. No. 372,598 16 Claims. (Cl. 49-431) This invention relates to a take-out window of the double-hung sash type. It is an object of the invention to start with a standard double-hung sash window and frame, and convert it to a take-out window which is easy to operate, the changeover being made by means of a minimum of alterations of the frame and sashes.

The standard or customary double-hung window has an upper and a lower sash, each of which is counterbalanced by weights or springs so as to be easily raised and lowered. To make such a window over into a takeout window, it is necessary to arrange for simple and easy disconnection of each sash from its counterbalancing mechanism, and to see to it that the take-out window is as nearly air-tight as the standard window when closed. In the following description of an embodiment of the invention and in some of the claims, the sashes are for convenience described as being vertically slidable. However, the frame with the sashes can be rotated 90, if desired, so that the sashes slide horizontally, in which case no counterbalancing devices are necessary but the sashes are readily removable from the frame in the same manner as are the vertically slidable sashes.

To achieve these results, a metal jamb liner is mounted in each of the vertical channels in which the stiles of the sashes slide. Each of these metal liners has a vertical, narrow rib extending from top to bottom thereof somewhat after the manner of metal weather-stripping. The side edges of the sashes have narrow slots into which these ribs extend part way. Small blocks are mounted in these slots near the corners of the sashes to maintain the sashes centered when in use so that they do not fall out of the window frame. As hereinafter explained, each sash has a certain position in the frame at which it can be shifted laterally sufficiently to clear the rib at one side edge so that that edge can be swun-g out to remove the sash from the frame. For clarity of description the structure will be described and illustrated in terms of shifting each sash toward the left to clear the right edge, but it will be understood that the direction can be reversed.

The coun-terbalancing means illustrated in the drawings consist of helical springs attached at their upper end to the frame near the top thereof, and a rod alongside of each spring, the lower end of each spring being attached to the lower end of its corresponding rod, each spring and its rod being located behind a jamb liner. From the upper end of each rod a cord or flexible wire extends through a small hole in the jamb liner to a small block which catches under a lower corner of one of the sashes :as hereinafter more fully described. When a sash is to be taken out, the little blocks to which the cords are attached are secured to the frame and the sash is lifted clear and raised to a level at which it can be shifted to the left for removal from the frame. When the sash is inserted in the frame the little blocks are then released from the frame so as to support the sash.

In order to provide for the removal of the sashes from the frame it has been necessary to cut away portions of the sashes. This results in air-passages which are objectionable. To block these passages, air-stops are provided to close the passages when the window is closed, as hereinaf-ter described.

Where springs have been used as counterbalancing devices for the sashes, some trouble has been experienced owing to the variation of the lifting force of the springs when the sashes are up or down. Thus when either sash is in its lowermost position, the springs which serve as its oounterbalancing means are more distended than when the sash is in a higher position where their lifting force is less. This may result in too strong a lift when a sash is down and too weak a lift when the sash is up. To remedy this fault, friction devices have been employed, but these tend to make it diflicult to raise or lower a sash. As hereinafter described, I provide simple means for initially opposing a change of direction of up or down movement of a sash, the sash being easily moved after the initial opposition has been overcome. Thus, for example, the upper sash is held in its top position in the frame in spite of the relatively weak action of its springs but readily moves downward after. the initial opposition to downward movement has been overcome by the application of a little extra force.

For a more complete understanding of the invention, reference may be had to the following description thereof, and to the drawings, of which:

FIGURE 1 is an elevational view of a double-sash window and its frame, most of the inside trim being omitted and portions of the lower sash being broken away;

FIGURE 2 is an elevational view of the lower sash raised to the upper part of the frame (inside trim omitted) in position to be taken out;

FIGURE 3 is an elevational view of the upper sash lowered to its take-out position in the lower part of the frame (inside trim omitted), the surrounding window frame being shown in section;

FIGURE 4 is a section on the line IVIV of FIG- URE 5;

FIGURE 5 is an elevation, on a larger scale, of part of the vertical metal jamb liner shown in FIGURE 1 on which the left hand edge of the lower sash slides;

FIGURE 6 is a section on the line VIVI of FIGURE 5, on a larger scale;

FIGURE 7 is a perspective view, from the outside, of the metal jamb liner on which the right hand edge of the upper or lower sash slides, intnrned flanges being broken away to show the members in the channel;

FIGURE 8 is a perspective view of the metal jamb liner on which the left band edge of the upper sash slides;

FIGURE 9 is a fragmentary perspective view of the left metal ja-mb liner for the lower sash with one of the sash-supporting blocks, the sash not being shown;

FIGURE 10 -is a fragmentary perspective view of the metal jamb liner on the right :for the lower sash and a supporting block for the lower sash;

FIGURE 11 is a perspective view, on a larger scale, of a supporting block for the right hand corner of the upper sash;

FIGURE 12 is a fragmentary section on the line XII XII of FIGURE 3, on a larger scale;

FIGURES 13 and 14 are sections similar to FIGURE 12, but showing the latch in different positions of operation;

FIGURE 15 is a fragmentary vertical section of one of the metal jamb liners, showing a hole with a supporting cor-d passing through it;

FIGURES l6 and 17 are fragmentary sections on the line XVI-XVI of FIGURE 20, on a larger scale;

FIGURE 18 is a perspective view of a cam rod, a part of which is shown on a larger scale in FIGURE 4;

FIGURE 19 is a similar View of a rod without the cam;

FIGURE 20 is an enlarged sectional view on the line XX-XX of FIGURE 1 as it would appear when the lower sash is raised, with the trim in place;

FIGURE 21 is a fragmentary perspective view of the upper left corner of the lower .sash in the closed position, and adjacent parts carried by the frame;

FIGURE 22 is a fragmentary perspective view of the upper left corner of a modified form of lower sash; and

FIGURE 23 is a fragmentary perspective view of a modified metal jamb liner for the left hand edge of the lower sash.

The embodiment of the invention illustrated in FIG- URES 1-21 is a double-hung window, the two sashes 30, 32 being vertically movable in a standard frame 34 and counterbalanced. The sashes are of the usual rectangular shape, the lower sash 30 including right and left stiles 36, 38, the upper sash 32 including right and left stiles 40, 42. The window frame 34 comprises a head jamb 44, side jambs 46, 48, sill 50, filler strips 54, stops 56 (a filler strip and a stop being indicated in FIGURE 20 but not shown in FIGURE i1), par-ting strips 58 on the respective side jambs 46, 48, and outside casing 59, and an inside casing 60, the casings 59 and :60 being omitted in FIGURE 1. The parting strips are between the customary vertical channels in which the stiles slide.

In some cases it may be preferred to have only the lower sash removable .as then the outside of the upper sash can be reached for cleaning with little difiiculty. However, the structure hereinafter described prov-ides for the rem-oval of both sashes from the frame.

Mounted against the right hand jamb 46 are two metal jamb liners 62 which may be similar in structure, one of them being shown in FIGURE 7. Each liner comprises an elongated box-like structure which may be partly open on one side, as shown, but has a narrow rib or fi-n 66 projecting from the other side. Each liner 62 and its rib 66 extend vertically from the sill to the head jamb, the rib projecting toward the opposite side of the window frame. With-in each liner on the right and the liner on the left for the upper sash is a rod 68 which is about half the length of the liner and occupies about half the cross-sectional area of the box-like structure. Within the liner on the left of the lower sash is a modified rod 68'. Beside the rod 68 or 68 within the liner is a helically coiled tension spring 70 the upper end of which is caught on or fastened to the top of the liner, the lower end of the spring being attached to the lower end of the rod 68 or 68'. An ear 72 is provided at the lower end of the rod to which the spring is attached. A flexible cord or wire 74 is attached to the upper end of the rod 68 or 68' and is carried down through an opening 76 in the wall of the liner. At the lower right hand corner of the lower sash 30 the corresponding cord 74 is attached to a block 78. This block is fitted for sliding movement in the vertical channel between the rib 66 on which the right hand edge of the lower sash 30 slides and the adjacent stop 56 (not shown on the right). The block 78 has a small catch '80 projecting horizontally therefrom and engaging under the lower sash 30 at the right hand corner thereof. A similar block 82 with a catch 83 (FIGURE 9), attached to the cord 74 at the left of the lower sash, supports the lower left hand corner of the lower sash and applies, with the block 78, the counterbalancing forces of the springs 70 to help raise the lower sash 30. The block 82 slides on the jamb liner 62a at the left of the lower sash, and its cord 74 passes through an aperture 76 in the wall of that jamb liner. The aperture is made by striking out a tab 84 which serves as a stop for the block 82 when the beveled top of the block engages under the tab 84.

The upper sash is similarly supported by movable blocks which are connected by cords or wires 74 and rods 68 to springs 70. The blocks for supporting the upper sash differ from the blocks '78 and 82 and arehereinafter described.

The jamb liners on the left are similar to those on the right except that a portion of each rib is cut away to permit the removal of the sashes from the frame. The rib 66a of the jamb liner 62a at the left of the lower sash is notched near the upper end thereof at 85, this notch exposing a bit of the parting strip 58 in FIGURE 1. In like manner, the rib 66b of the jamb liner 62b at the left of the upper sash is notched at 86 a little below the mid point of this liner (FIGURE 3). The side edges of the sashes are deeply grooved (as indicated at 88, 90 in FIGURE 20) to receive the corresponding ribs of the jmab liners. The width of each sash is greater than the distance between the edges of opposing ribs of the jamb liners but less than the distance between the edge of the rib on one jamb liner and the body of the opposing jamb liner so that if a sash is shifted to the left to touch the body of the opposing jamb liner, the right hand edge of the sash will clear the rib which normally extends into it. The sash can then be swung forward from its normal plane until its right edge is clear of the window frame whereupon the sash is taken out by shifting it to the right.

When the window is in normal condition, the sashes must be kept centered. For this purpose the grooves are shallower at their upper ends so that the ribs touch or nearly touch the bottoms of the grooves at these points. For convenience, the grooves may be cut to uniform depth and spacer blocks 91, 92 may be fixed therein, preferably at or near the upper corners of the lower sash 30 to reduce the depth of the grooves at those points and to engage the edges of the corresponding jamb liner ribs to keep the top of the lower sash centered. The movable blocks 78, 82 keep the bottom of the lower sash centered. Additional centering means comprise a block 93 on the stile 36 near the lower end thereof, bearing on the edge of the adjacent rib 66, and a block 94 near the lower end of the stile 38 bearing on the edge of the rib 66a. If either cord 74 should break or the counterbalancing means should be omitted (as would be the case if the window frame were mounted with its long axis horizontal), the centering function for the lower part of the sash 30 would be taken over by the blocks 93 and 94. A notch 95 is made in the rib 66a to receive the block 94 when the lower sash is raised for removal. The notch 95 is shorter than the block 92 so that the latter cannot enter this notch when the lower sash is being raised. The spacing between the notches 95 and 85 is the same as that between the blocks 94 and 92. When the lower sash is to be taken out, it is raised until the blocks 94 and 92 are on a level respectively with the notches 95 and 85 in the rib 66a. A stop 97 on the rib is engaged by the upper left corner of the sash when this level is reached. Part of the material cut away to form the notch 85 may be used for the stop 97. Just before the lower sash reaches that height, the supporting blocks 78, 82 stop rising as they reach the openings 76 through which the cords 74 pass into the interior of the liners. Further raising of the lower sash clears it from the blocks 78, 82 which then ceases to center the lower sash and it can be shifted to the left when the blocks 94 and 92 are on a level, respectively, with the notches 95 and 85 to clear the rib on the right for removal from the frame. To restore the lower sash to the frame, the left hand edge is moved into the frame channel containing the corresponding jamb liner, the sash being held at the height at which its blocks 94 and 92 are on a level, respectively, with the notches 95 and 85 so that the right edge of the sash can be swung in until its groove is opposite the rib 66 of the corresponding jamb liner. The sash is then shifted to the right and lowered. The shift to the right may be done initially by the operator or by the blocks 92 and 94 as they are cammed out of the notches 85 and 95 by the downward movement of the sash. If there is no block 94, the sash will be cammed to the right by the block 92 and the tab 84. The bottom corners of the sash engage the blocks 78, 82 which then support the sash and help to center its bottom.

The upper sash 32 is removable from the frame in much the same way as the lower sash except that its supporting blacks 96, 98 (FIGURE 3) must be secured to the frame before the sash can be lifted clear. These supporting blocks are each connected by a cord or wire 74 to the upper end of a rod 68 which is slidable in one of the jamb liners. A spring 70 is beside the rod 68 within the jamb liner and is attached at its lower end to the lower end of the rod, the upper end of the spring being attached to the upper end of the jamb liner in which it is housed.

The side edges of the upper sash 32 are grooved like the. edges of the lower sash. In these grooves spacer blacks 106, 108 are mounted near the upper ends and spacer blocks 107, 109 are mounted near the lower ends to bear against the opposing ribs so as to keep the upper sash centered. The lower blocks 96, 98, when they are supporting the upper sash, help to keep it centered. When the upper sash 32 is to be taken out, it is first moved down until its blocks 96, 98 hit the sill 50 and are anchored there by means hereinafter described. The upper sash is then lifted slightly to bring the blocks 108 and 109 on a level with the notches 86 and 111 respectively,

and to lift the sash clear of the blocks 96, 98. The sash is then shifted to the left, the right edge is swung out of the frame and the sash is shifted to the right to separate it completely from the frame. To restore the sash to its place in the frame, the reverse movements are made.

To anchor the support blocks 96, 98 to the frame, a catch 110 is provided in each to project through an aperture 112 in the rib 66 or 66b which is beside the block. The right hand block 96 is illustrated in FIGURES 11-14. The block 98 is a mirror image of this block and operates in exactly the same way so that a description of the structure and operation of the block 96 will serve for the block 98.

The block 96 has a shelf or catch 114 (FIGURE 11) on which a corner of the upper sash rests when supported by the blocks. The block has a transverse slot 116 extending up from the bottom thereof. When the block is down as far as it can go, the slot 116 registers with the aperture 112 in the rib 66 which is next to it as indicated in FIGURE 12. Movably mounted in the slot 116 is a plate 120 at an upper corner of which is the catch 110, the opposite upper corner having a flange 122. The lower portion of the plate 120 projects below the bottom of the block 96, the end of the plate being bent to form a foot .124 to engage the sill 50 when the upper sash is lowered as far as it will go. The plate 120 is retained in the slot by two pins 126, 128 which pass respectively through a triangular hole 130 with a notch 131 at its lower end and a slot 132 through the plate. As seen in FIGURES l'214, a hairpin spring 134 presses against the flange 122 tending to rock the plate clockwise about the pin 128. Ordinarily, the plate 120 is in the position illustrated in FIGURE 14, the catch 110 being entirely Within the slot 116. When the upper sash is to be taken out, it is first moved down until the foot 124 hits the sill 50. This forces the plate 120 upward so that edges of the hole 130 and slot 132 cam the plate toward the left to the position shown in FIGURE 12 wherein the pin 126 engages in the notch 131 and the catch 110 projects from the block 96 through the aperture 112 which is then in line with it. When the sash is then raised slightly, .the pins 126, 128 in the notch 131 and slot 132 keep the catch 110 projecting outward until the catch 110 engages the upper end of the aperture 112, whereupon further upward movement of the block 96 causes the pins to move to the upper ends of the hole 130 and slot 132 as shown in FIGURE 13. At the same time, a similar operation takes place in the block 98. The blocks 96 and 98 are now anchored by the catches 110 so that the upper sash can be raised a little further, clear of the blocks 96 and 98,

for removal from the frame as described. When the, sash is reinserted in the frame, the left-hand edge going in first, the sash is pushed downward until it engages the blocks 96, 98. A slight further push downward disconnects the catch 1-10 of the block 96 from its engagement with the rib 66 at the upper end of the aperture 112. As the pin 126 is then at the upper or broad end of the hole (FIGURE 13) the spring 134 can rock the plate 120 clockwise to the position shown in FIGURE 14. In like manner the block 98 is released from the frame, permitting both blocks to rise with the upper sash as the latter is elevated to its normal position.

A small pin 136 is mounted on the shelf 114 of the block 96 to fit into a small hole (not shown) in the bottom of the upper sash. If in the process of taking out the upper sash the block 96 fails to anchor itself when the sash is pushed all the way down, the block will rise with the sash when the sash is raised and the pin 136 will prevent the right edge of the sash from being swung clear of the frame. If the block 98 fails to anchor itself, when it should, it will rise with the sash and prevent any shift of the sash to the left for sash removal. Thus both of the blocks 96- and 98 must be properly anchored before the upper sash can be removed from the frame.

To supplement the counterbalancing operation of the springs 70, the grooves in the side edges are preferably made wide enough not only to receive the ribs of the jamb liners but also to be lined on both sides with a pile fabric 138 (FIGURES 16 and 17), the width of the grooves being such as to cause the pile to meet the rib at an angle. If the side faces of the rib are not too smooth, the minute irregularities of the surfaces will catch on the ends of the pile so that a reversal of movement of the sash will be,

opposed by tthe force required to change the angular position of the pile from that shown in FIGURE 16 to that shown in FIGURE 17, the magnitude of the resisting force depending on the stiffness of the pile and its angle of incidence. Such angle should be approximately 30. Too small an angle of incidence results in too easy a reversal of the pile and consequently an insufficient force opposing change in the direction of movement of the sash. If the angle of incidence is too great the pile is apt to slip on the surface of the rib or to buckle instead of reversing the angle of incidence. This. yielding initial resistance to change of direction of movement of a sash serves to hold the lower sash down in its lowest position in spite of the fact that the springs 70 connected to that sash exert their maximum lifting force when the sash is in that position. In like manner, the pile fabric linings serve to hold the upper sash in its uppermost position in spite of the fact that the lifting effect of the springs connected to that sash then exert the minimum lifting force. To augment this effect, opposed pairs of small leaves 139 of flexible material, such as soft rubber, may be mounted at intervals in the grooves, the length of each leaf being approximately the same as that of the pile. Another factor helping to hold a sash releasably in any position of adjustment up or down is the snubbing effect on the cords 74 where they are reversely bent in passing through the holes 76 as indicated in FIGURE 15. These holes are small and the wall portions immediately above and below them are curved to avoid contact of the cordswith edges which would result in excessive wear. The use of pile fabric to offer initial resistance only to a change of direction of motion of one object which is relatively movable with respect to another can be applied to structures other than window frames and sashes.

In order to be serviceable, a window must be reasonably air-tight when closed. For this purpose, in ordinary double-sash window construction, the meeting rails (top rail of the lower sash and bottom rail of the upper sash) which are at the same level when the window is closed project from the planes of the sashes to lap each other horizontally, the lapping portions being pressed together by the usual window lock to make a tight joint between the sashes. Such a projetcion of the top rail of a lower sash is illustrated at 140 in FIGURES 21 and 22. Since he stiles of the sashes of ordinary construction bear .gainst the sides of the parting strips 58, the projections |f the meeting rails at their ends lap the parting strips. 11 the take-out windows described herein, the sashes must )6 shifted to the left in the process of removing them from he frame. This requires that the left end of the meeting ails be cut away as at 142 so that the parting strip will lOt prevent such a shift. This leaves an air passage which must be stopped when the window is closed. For this lurpose an air-stop 144 in the form of a small block is ecured to the parting strip 58 at the left at the level of he meeting rails, the block being of a size to fit the tOtChfiS 142 in the left end of the meeting rails. The lock may be of any suitable material such as felt held a place by a thin metal ribbon 146. Since neither sash in its closed position when about to be taken out, the lock 144 does not interfere with the necessary shift to he left.

Other air passage result from the width of the sashes Ieing less than the distance between the jamb liners. Vhen the sashes are centered as they always are except vhen being taken out or put back in, there is considerable .learance between each side edge of the sashes and the adacent jamb liner. The blocks 96, 98 serve to close the learances between the side edges of the upper sash and he adjacent jamb liners. To stop the air pass-age at the ight of the lower sash, a block 148 (FIGURE 1) is iounted in the space between the right hand edge of the Dwer sash and the adjacent parting strip, jamb liner and ib at the level of the top rail when the window is closed. corresponding fixed block cannot be mounted at the left f the lower sash as that would prevent the necessary hift to the left to take out the sash. Instead, a movable lock 150 is supported by a spring 152 in an aperture 54 in the wall of the jamb liner 62a. The block is norially supported in the position shown in FIGURE 4, ubstantially flush with the wall of the jamb liner. The od 68 (FIGURE 18) in this jamb liner is cut away as t 156 to make room for the spring 152 and to act as cam to push the block 150 out through the hole 154 /hen the rod is pulled down by the lower sash to which is connected by a cord 74. When the lower sash is aised to its take-out position, the block 150 is within the imb liner and does not interfere with the shift to the :ft. When the lower sash is in the closed window posilon, the rod '68 holds the block in the projected position 3 block the air passage-between the edges of the sash, 1e jamb liner 62a, the rib 66a and the parting strip 58.

Instead of the movable block 150, a block 158 may be iounted on the upper left corner of the lower sash, as idicated in FIGURE 22. An opening 159 is provided ear the upper end of the jamb liner 620 in position to eceive the block 158 when the sash is raised to the takeut position in which the block 94 is on a level with the otch 85. The sash can then be shifted to the left.

The material cut from the jamb liner to form the openig 159 may be used as a stop 162 to limit the upward iovement of the rod 68' in the liner.

I claim:

1. A window structure compriisng a frame including sill, side jambs with parting strips and a head jamb, n upper and a lower sash slidable vertically in said frame, tmb liners for said lower sash mounted against said side lIIlbS, counterbalancing means within said jamb liners aving elements engaging under said lower sash for suport thereof, a vertical rib on each said jamb liner project- Jg toward the opposite liner, said lower sash having a vercal groove in each side edge thereof in which said ribs re respectively received, one of said grooves being relavely shallow near the upper end thereof for contact 'ith the edge of the rib therein to maintain the lower ash centered with respect to said frame, the remainder of aid groove being deeper for spacing between the bottom f the groove and the edge of the rib therein, the last lentioned rib being cut away near the top thereof to resash is sufficiently raised whereby said lower sash can 'be shifted sidewise to move the other edge of the sash clear of the other rib for the removal of the lower sash from said frame.

2. A window structure as described in claim 1, each of said jamb liners having a small hole therethrough at a level near the top of the lower sash when in closed position, said counterbalancing means comprising at each side of the lower sash a cord extending through the hole in the jamb liner, a catch secured to an end of the cord and normally engaging under a lower corner of said lower sash, and tensioning means within the jamb liner attached to the other end of the cord.

3. A window structure as described in claim 2, said tensioning means comprising a helically coiled spring and a rod disposed side by side in each said jamb liner, said spring having its upper end fixed to said frame and its lower end attached to the lower end of the adjacent rod, said other end of the cord being attached to the upper end of the rod.

4. A window strutcure as defined in claim 3, said lower sash having a top rail an end of which is cut away to permit lateral shifting of the upper portion of the lower sash from its normal centered position, and an air-stop comprising a block secured to the parting strip adjacent to said cutaway portion of said top rail normally closing the airway resulting from the cutaway portion of said top rail.

5. A window structure as defined in claim 3, the width of the lower sash being less than the horizontal distance between said jamb liners, whereby an air passage is formed between each side edge of said lower sash and the adjacent jamb liner, rib and parting strip and means for closing said air passages when the window is closed, said closing means consisting of a fixed block in one of said air passages secured to a jamb liner, and a movable block normally within the other said air passage and yieldingly supportedby the adjacent jamb liner.

6. A window structure as defined in claim 5, the jamb liner adjacent to the cutaway end of said top rail having an aperture through which said movable block is adapted to move, the supporting means for said block comprising a leaf spring within the jamb liner attached to said block and normally supporting the block within the jamb liner and flush with the surface of the jamb liner wall, the rod in said jamb liner having a cam surface bearing on said spring when the lower sash is lowered to project said block through said aperture into position to close the adjacent air passage.

7. A window structure as described in claim 1, jamb liners for the upper sash mounted against said side jambs of the frame, the last mentioned jamb liners each having a vertically extending rib projecting toward the opposite side of the frame, said upper sash having a vertical groove in each side edge in which one of said ribs engages, means in said grooves centering said upper sash except when it is at a predetermined level for removal from the frame, the counterbalancing means for the upper sash comprising a block having a catch engaging under each lower corner of the upper sash, a cord attached at one'end to each said block, a coiled spring and a rod arranged side by side in each said jamb liner, each said spring being fixed at its upper end to the frame and attached at its lower end to the lower endof the adjacent rod, the other end of each said cord being attached to the top of the corresponding rod.

8. A window structure as described in claim 7, each of said blocks which engage under the corners of the upper sash having lat-ch means therein including a normally retracted catch adapted to be projected outward by engagement of the block with the sill to catch on the adjacent rib when the block is raised slightly from the sill, and means retracting said catch into the block when released from said rib.

9. A window structure comprising a four-sided frame are mutually parallel, one of said sashes having a groove in each of its edges which are adjacent to said parallel sides of the frame, and a rib projecting from each of said parellel sides of the frame and extending into said grooves respectively, one of said grooves being relatively deep for most of its length so that its bottom is spaced from the edge of the rib therein, said deep groove having a shallow portion wherein the bottom thereof is touched by said rib, said rib having a notch therein to receive the shallow portion of the groove 'when opposite said notch where by the sash can then be shifted in its plane to clear its opposite edge from the other rib for the removal of the sash from the frame.

10. A window structure as described in claim 9, in which the other sash is similarly removable from the frame.

11. A window structure comprising a four-sided frame and two sashes slidable between two of said sides which are mutually parallel, one of said sashes having a groove in each of its edges which are adjacent to said parallel sides of the frame, and a rib projecting from each of said parallel sides and extending into said grooves respectively, one of said grooves being relatively deep for most of its length so that its bottom is spaced from the edge of the rib therein, said deep groove having a shallow portion near each end thereof wherein the bottom thereof is touched by said rib, said rib having two notches therein spaced apart to receive simultaneously said shallow portions of said groove when opposite said notches, whereby said sash can then be shifted in its plane to clear its opposite edge from the other rib for the removal of the sash from the frame.

12. A window structure as described in claim 11, the upper of said shallow portions of said groove being longer than the lower of said notches, whereby said upper portion cannot ride into said lower notch when said grooved sash is raised or lowered.

13. A double-hung sash window structure comprising a frame including a sill, side jams and a head jamb, parting strips defining vertical channels with said side jambs, an upper and lower sash having stiles vertically slidable in said channels, each stile of the lower sash having a vertical groove, the adjacent side jamb of the frame having a vertical rib engaging in the groove, means on each groove coacta'ble with the vertical ribs automatically offering initial resistance to both upward and downward movement of the lower sash, but offering reduced resistance once movement in either direction has commenced.

14. A double-hung sash window structure comprising a frame including a sill, side jambs and a head jamb, parting strips defining vertical channels with said side jambs, an upper and a lower sash having stiles vertically slidable in said channels, each stile of the lower sash having a vertical groove, the adjacent side jamb of the frame having a vertical rib engaging in the groove, the sides of each said groove being lined with a pile fabric engaging the side faces of the corresponding rib, the width of each said groove being such that the pile engages the rib at an angle of approximately 30 whereby to oppose changes of direction of vertical sliding movements of said lower sash.

15. A frame having a pair of parallel :members, an object slidably mounted between said members and movable in opposite directions, said object and parallel members having mutual-1y confronting surf-aces uniformly spaced apart, one of said surfaces being rough, the other surface having thereon a pile fabric with pile sufficiently longer than the distance between said surfaces to engage said rough surface at an angle of approximately 30.

16. A frame having a pair of parallel members, an object slid-ably mounted between said members and movable in opposite directions, said object and parallel members having mutually confronting surfaces uniformly spaced apart, one of said surfaces being rough, the other surface -having thereon a pile fabric with pile sufficiently longer than the distance between said surfaces to engage said rough surface at an angle of approximately 30, and flexible leaves of resilient material embedded in said pile fabric, said leaves having free edges flush with the ends of the pile.

References Cited by the Examiner UNITED STATES PATENTS 676,159 6/1901 Stumpf 2052.2 X 2,294,851 9/ 1942 Owen 20-52 X 2,372,634 3/1945 Breiten Bach 29274 2,599,196 6/1952 Peremi. 2,790,214 4/ 1957 Edwards et -al 2069 2,921,348 1/ 1960 Nardulli 2052 2,965,935 12/1960 Olsen 2052.2

HARRISON R. MOSELEY, Primary Examiner.

A. I. BREIER, Assistant Examiner. 

13. A DOUBLE-HUNG SASH WINDOW STRUCTURE COMPRISING A FRAME INCLUDING A SILL, SIDE JAMS AND A HEAD JAMB, PARTING STRIPS DEFINING VERTICAL CHANNELS WITH SAID SIDE JAMBS, AN UPPER AND LOWER SASH HAVING STILES VERTICALLY SLIDABLE IN SAID CHANNELS, EACH STILE OF THE LOWER SASH HAVING A VERTICAL GROOVE, THE ADJACENT SIDE JAMB OF THE FRAME HAVING A VERTICAL RIB ENGAGING IN THE GROOVE, MEANS ON EACH GROOVE COACTABLE WITH THE VERTICAL RIBS AUTOMATICALLY OFFERING INITIAL RESISTANCE TO BOTH UPWARD AND DOWNWARD MOVEMENT OF THE LOWER SASH, BUT OFFERING REDUCED RESISTANCE ONCE MOVEMENT IN EITHER DIRECTION HAS COMMENCED. 